1. Field of the Invention
The present invention relates to a switch with a magnetic drive having an armature which can be displaced between two end positions and is connected with a least one movable switch contact, and which in the end positions is under the influence of magnetically generated forces.
2. Description of Related Art
Here, switch is understood to be a device which switches on nominal currents or excess currents under certain conditions, resists the nominal or excess currents and interrupts them, as well as insulates electrical circuits from each other. To this end a switch has two stable states (states of rest requiring holding forces). In the open state the switch is capable of maintaining the electrical insulation of the circuits. In the closed state the switch is capable of resisting the defined nominal current permanently and an excess current for a defined amount of time.
The switch furthermore has two transition stages in which energy is supplied to a movable switching element. The transition into the closed state is intended to close a circuit and turn on a current. The transition into the open state is intended to interrupt a current. The main components of such a switch are: connecting terminals, switch chamber, quiescent current or operating current contacts, a drive mechanism for actuating the movable switching contacts, and a housing in which the above described elements are arranged and which insulates the circuits. Switches of this type are also known by the name power circuit breakers.
An electrical switch of the type described at the outset is known (DE 43 04 921 C1). The armature of this switch is made of laminated soft iron sheets and is axially displaceably arranged in a chamber surrounded by a rectangular yoke made of laminated soft iron sheets between two permanent magnets, whose like poles face the armature. The permanent magnets are respectively stationarily attached between the armature and a pole piece which makes a transition into the yoke. A coil is respectively arranged inside the yoke on both sides of the pole pieces.